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Aug 12, 2023

How Scientists Are Saving the Endangered Galapagos Pink Iguana

Gear-obsessed editors choose every product we review. We may earn commission if you buy from a link. Why Trust Us? Researchers used solar-powered GPS tags to track the elusive lizard right into an

Gear-obsessed editors choose every product we review. We may earn commission if you buy from a link. Why Trust Us?

Researchers used solar-powered GPS tags to track the elusive lizard right into an active volcano. Here’s how they’re hoping to bring the species back from the brink.

In 2009, when scientists revealed they had discovered a new species of iguana living in the Galapagos Islands, the announcement was bittersweet. While the four-foot-long, blush-colored lizard with powerful legs and razor-sharp claws was a stunning find in one of the world’s most well-studied places, the Galapagos pink iguana was immediately classified as critically endangered.

“We immediately knew that it needed urgent conservation action,” Gabriele Gentile, the University of Rome Tor Vergata zoologist who first described the species, told Popular Mechanics.

There are an estimated 200 to 300 pink iguanas left in the world, and all of them live near the top of Wolf Volcano on Isla Isabela, one of the highest, most remote places in the Galapagos Islands. The location is so hard to get to, it’s rarely visited by people, including scientists. However, feral cats introduced by early settlers do roam the island and are likely the reason researchers have never seen a juvenile pink iguana in the wild. Because these lizards evolved without mammalian predators, young iguanas have no defenses against these destructive felines.

Compounding the danger for the tiny population of pink iguanas is that the volcano they call home is an active one, erupting as recently as January 2022. Fortunately, the latest eruptions have been minor, but researchers like Gentile are understandably worried that one severe eruption could doom the pink iguana to extinction.

To ensure the survival of the species, Gentile and his colleagues, in collaboration with the San Diego Zoo Wildlife Alliance, decided to launch a “head-starting” program to bolster population growth. Head-starting consists of gathering recently hatched iguanas and taking them to a rearing facility so that they can grow and develop in a safe place away from predators. When the iguanas are old and large enough to fend off feral cats, they are returned to their range, where they can perpetuate the species. (Meanwhile, an Ecuadorian nonprofit would work on controlling the feral cat population.)

But in order for the head-start program to begin, scientists needed to figure out where the lizards were nesting—in an area that is virtually inaccessible to humans. There are no trails that lead to the iguanas’ habitat, and no water or cell signal on the way, either.

So engineers at the University of Rome Tor Vergata spent a few years designing an iguana-appropriate GPS tracking device, an instrument usually used on much larger animals. Gentile says the team opted for solar-powered supercapacitors over batteries, which keep the load light for the iguana and prevent unintended pollution of spent batteries. In addition to GPS sensors, the devices also contain a thermometer, a hygrometer, a UV light reader, and a 250mg memory card. A small antenna sends data to a ground station, which then sends that info onto scientists via satellite.

In 2019, Gentile and his team took a helicopter ride to the top of Wolf Volcano and fitted 15 iguanas with the GPS devices, using medical stitches and epoxy to make sure they were completely secure.

In the three years since the team has been tracking the rosy lizards, they’ve learned a lot about their seasonal movements and, most importantly, when and where the females are nesting. Every year from late April to early June, female pink iguanas leave their mates and move into the volcano’s caldera to a shelf about 1,700 feet down, or halfway to the caldera’s floor.

“The outside slopes of the volcano are so rocky, and the females need dirt and sand to nest,” Gentile explained. “The rim is constantly eroding and creating piles of dust” inside the volcano, where females lay their eggs, patrolling the nearby area for about ten days afterward.

Going forward, the team is hoping to tag more iguanas and follow them into the caldera so they can study, mark, and protect their nesting sites, in preparation for removing hatchlings in the near future.

For Gentile, who first heard rumors of pink iguanas back in 2000 when he was studying tortoises in the Galapagos, two decades studying the pink iguana has been both a scientific and emotional endeavor: “I’ve completely fallen in love with iguanas.”

Ashley Stimpson is a freelance journalist who writes most often about science, conservation, and the outdoors. Her work has appeared in the Guardian, WIRED, Nat Geo, Atlas Obscura, and elsewhere. She lives in Columbia, Maryland, with her partner, their greyhound, and a very bad cat.

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